US Republican presidential frontrunner Donald Trump and party rival Ted Cruz feud over their wives after stirring controversies about them.
Cruz on Thursday branded Trump a "sniveling coward" as the war of words between the Republican contenders over their wives took a nastier turn.
The verbal attack came after Trump’s earlier threat to "spill the beans" on Cruz’s wife, Heidi.
The spat erupted in the wake of the recent publication by an anti-Trump group of a decade-old nude photo of his wife, Melania, when she was a model before marrying him.
Trump attributed the advertisement to the Cruz campaign and warned him on Twitter, "Be careful, Lyin' Ted, or I will spill the beans on your wife!"
He also tweeted side-by-side images of Cruz's wife and his own spouse, saying, "No need to spill the beans. The images are worth a thousand words."
This prompted Cruz to lash out at Trump on Thursday, warning him to "leave Heidi the hell alone."
Cruz also said Trump was a ‘coward’ who "does seem to have an issue with women."
The row is the latest in a string of personal spats between the contenders to win the GOP slot for America's November presidential election.
The campaign for Republican nomination has been marred by countless instances of scandals, mudslinging and onstage vulgarity, where rivals have time and again seized opportunities to blacken their opponents and push them down the gutter.